@ dreamcast270mhz:
My mother's Aspire One is much weaker than my iBook, and I watch a lot of DVDs on the go, I don't have the time to handbrake them all onto a netbook with a squashed screen and cruddy sound. I just don't have a use for them, my iBook serves its purpose well
The CPU should be comparable, but I agree that OS requirements might be a problem - Vista etc. If you watch DVDs then I understand for you iBook is probably the better machine, BUT squashed screen? iBook is 4:3 and netbooks 16:9 and it's 12" vs 10.1", which means that you have practically the same viewing area for widescreen films (netbooks might even win here) and cruddy sound? I seriously doubt your iBook's speakers are hi-fi quality (I know they weren't on my G3 IceBook) so headphones are a must in both cases if you want decent sound.
Still, I get it that for you iBook is fine, but there are others who value portability above all else (e.g. me) and iBooks certainly cannot compete with netbooks in weight and size.